The purpose of this invention is to protect personnel from the threat of eye damage or blindness when irradiated with a laser beam of sufficiently high power by an adversary. Similarly, this invention provides a means to protect optical components, such as TV cameras and detectors, from laser-induced damage.
In situations when the potential laser threat is known beforehand (i.e., wavelength, direction of propagation, pulsed or CW, power and energy level), various means to protect personnel or equipment are available. Such protective apparatus would, for example, consist of neutral density filters, narrow band wavelength filters, individual wavelength selective absorption filters, mechanical shutters and combinations of these items. The protective apparatus would be designed for a particular, known threat. Some of these techniques have their concomitant disadvantages such as time to respond or broad wavelength band insertion loss, inhibiting normal visual use.
For these reasons, the above-mentioned means are not entirely practical nor effective in providing the needed safety. The wavelength, pulsed or CW, of an irradiating laser source may be an unknown factor to contend with in the same way that unknown radar threats are encountered. A basic requirement of any protective system in a threatening situation is that the observer (human, camera, or detector), be able to see the surroundings with minimal visual loss (attenuation or distortion) while being protected from laser damage.